Merge branch 'bpf-link-support-for-tc-bpf-programs'

Daniel Borkmann says:

====================
BPF link support for tc BPF programs

This series adds BPF link support for tc BPF programs. We initially
presented the motivation, related work and design at last year's LPC
conference in the networking & BPF track [0], and a recent update on
our progress of the rework during this year's LSF/MM/BPF summit [1].
The main changes are in first two patches and the last two have an
extensive batch of test cases we developed along with it, please see
individual patches for details. We tested this series with tc-testing
selftest suite as well as BPF CI/selftests. Thanks!

v5 -> v6:
  - Remove export symbol on tcx_inc/dec (Jakub)
  - Treat fd==0 as invalid (Stan, Alexei)
v4 -> v5:
  - Updated bpftool docs and usage of bpftool net (Quentin)
  - Consistent dump "prog id"/"link id" -> "prog_id"/"link_id" (Quentin)
  - Reworked bpftool flag output handling (Quentin)
  - LIBBPF_OPTS_RESET() macro with varargs for reinit (Andrii)
  - libbpf opts/link bail out on relative_fd && relative_id (Andrii)
  - libbpf improvements for assigning attr.relative_{id,fd} (Andrii)
  - libbpf sorting in libbpf.map (Andrii)
  - libbpf move ifindex to bpf_program__attach_tcx param (Andrii)
  - libbpf move BPF_F_ID flag handling to bpf_link_create (Andrii)
  - bpf_program_attach_fd with tcx instead of tc (Andrii)
  - Reworking kernel-internal bpf_mprog API (Alexei, Andrii)
  - Change "object" notation to "id_or_fd" (Andrii)
  - Remove on stack cpp[BPF_MPROG_MAX] and switch to memmove (Andrii)
  - Simplify bpf_mprog_{insert,delete} and add comment on internals
  - Get rid of BPF_MPROG_* return codes (Alexei, Andrii)
v3 -> v4:
  - Fix bpftool output to display tcx/{ingress,egress} (Stan)
  - Documentation around API, BPF_MPROG_* return codes and locking
    expectations (Stan, Alexei)
  - Change _after and _before to have the same semantics for return
    value (Alexei)
  - Rework mprog initialization and move allocation/free one layer
    up into tcx to simplify the code (Stan)
  - Add comment on synchronize_rcu and parent->ref (Stan)
  - Add comment on bpf_mprog_pos_() helpers wrt target position (Stan)
v2 -> v3:
  - Removal of BPF_F_FIRST/BPF_F_LAST from control UAPI (Toke, Stan)
  - Along with that full rework of bpf_mprog internals to simplify
    dependency management, looks much nicer now imho
  - Just single bpf_mprog_cp instead of two (Andrii)
  - atomic64_t for revision counter (Andrii)
  - Evaluate target position and reject on conflicts (Andrii)
  - Keep track of actual count in bpf_mprob_bundle (Andrii)
  - Make combo of REPLACE and BEFORE/AFTER work (Andrii)
  - Moved miniq as first struct member (Jamal)
  - Rework tcx_link_attach with regards to rtnl (Jakub, Andrii)
  - Moved wrappers after bpf_prog_detach_ops (Andrii)
  - Removed union for relative_fd and friends for opts and link in
    libbpf (Andrii)
  - Add doc comments to attach/detach/query libbpf APIs (Andrii)
  - Dropped SEC_ATTACHABLE_OPT (Andrii)
  - Add an OPTS_ZEROED check to bpf_link_create (Andrii)
  - Keep opts as the last argument in bpf_program_attach_fd (Andrii)
  - Rework bpf_program_attach_fd (Andrii)
  - Remove OPTS_GET before we checked OPTS_VALID in
    bpf_program__attach_tcx (Andrii)
  - Add `size_t :0;` to prevent compiler from leaving garbage (Andrii)
  - Add helper macro to clear opts structs which I found useful
    when writing tests
  - Rework of both opts and link test cases to accommodate for changes
v1 -> v2:
  - Rework of almost entire series to remove prio from UAPI and switch
    to better control directives BPF_F_FIRST/BPF_F_LAST/BPF_F_BEFORE/
    BPF_F_AFTER (Alexei, Toke, Stan, Andrii)
  - Addition of big test suite to cover all corner cases

  [0] https://lpc.events/event/16/contributions/1353/
  [1] http://vger.kernel.org/bpfconf2023_material/tcx_meta_netdev_borkmann.pdf
====================

Link: https://lore.kernel.org/r/20230719140858.13224-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 58 insertions, 12 deletions

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 600d0caebbd8..47b76925189f 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1036,6 +1036,8 @@ enum bpf_attach_type {
 	BPF_LSM_CGROUP,
 	BPF_STRUCT_OPS,
 	BPF_NETFILTER,
+	BPF_TCX_INGRESS,
+	BPF_TCX_EGRESS,
 	__MAX_BPF_ATTACH_TYPE
 };
 
@@ -1053,7 +1055,7 @@ enum bpf_link_type {
 	BPF_LINK_TYPE_KPROBE_MULTI = 8,
 	BPF_LINK_TYPE_STRUCT_OPS = 9,
 	BPF_LINK_TYPE_NETFILTER = 10,
-
+	BPF_LINK_TYPE_TCX = 11,
 	MAX_BPF_LINK_TYPE,
 };
 
@@ -1113,7 +1115,12 @@ enum bpf_perf_event_type {
  */
 #define BPF_F_ALLOW_OVERRIDE	(1U << 0)
 #define BPF_F_ALLOW_MULTI	(1U << 1)
+/* Generic attachment flags. */
 #define BPF_F_REPLACE		(1U << 2)
+#define BPF_F_BEFORE		(1U << 3)
+#define BPF_F_AFTER		(1U << 4)
+#define BPF_F_ID		(1U << 5)
+#define BPF_F_LINK		BPF_F_LINK /* 1 << 13 */
 
 /* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
  * verifier will perform strict alignment checking as if the kernel
@@ -1444,14 +1451,19 @@ union bpf_attr {
 	};
 
 	struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
-		__u32		target_fd;	/* container object to attach to */
-		__u32		attach_bpf_fd;	/* eBPF program to attach */
+		union {
+			__u32	target_fd;	/* target object to attach to or ... */
+			__u32	target_ifindex;	/* target ifindex */
+		};
+		__u32		attach_bpf_fd;
 		__u32		attach_type;
 		__u32		attach_flags;
-		__u32		replace_bpf_fd;	/* previously attached eBPF
-						 * program to replace if
-						 * BPF_F_REPLACE is used
-						 */
+		__u32		replace_bpf_fd;
+		union {
+			__u32	relative_fd;
+			__u32	relative_id;
+		};
+		__u64		expected_revision;
 	};
 
 	struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
@@ -1497,16 +1509,26 @@ union bpf_attr {
 	} info;
 
 	struct { /* anonymous struct used by BPF_PROG_QUERY command */
-		__u32		target_fd;	/* container object to query */
+		union {
+			__u32	target_fd;	/* target object to query or ... */
+			__u32	target_ifindex;	/* target ifindex */
+		};
 		__u32		attach_type;
 		__u32		query_flags;
 		__u32		attach_flags;
 		__aligned_u64	prog_ids;
-		__u32		prog_cnt;
+		union {
+			__u32	prog_cnt;
+			__u32	count;
+		};
+		__u32		:32;
 		/* output: per-program attach_flags.
 		 * not allowed to be set during effective query.
 		 */
 		__aligned_u64	prog_attach_flags;
+		__aligned_u64	link_ids;
+		__aligned_u64	link_attach_flags;
+		__u64		revision;
 	} query;
 
 	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
@@ -1549,13 +1571,13 @@ union bpf_attr {
 			__u32		map_fd;		/* struct_ops to attach */
 		};
 		union {
-			__u32		target_fd;	/* object to attach to */
-			__u32		target_ifindex; /* target ifindex */
+			__u32	target_fd;	/* target object to attach to or ... */
+			__u32	target_ifindex; /* target ifindex */
 		};
 		__u32		attach_type;	/* attach type */
 		__u32		flags;		/* extra flags */
 		union {
-			__u32		target_btf_id;	/* btf_id of target to attach to */
+			__u32	target_btf_id;	/* btf_id of target to attach to */
 			struct {
 				__aligned_u64	iter_info;	/* extra bpf_iter_link_info */
 				__u32		iter_info_len;	/* iter_info length */
@@ -1589,6 +1611,13 @@ union bpf_attr {
 				__s32		priority;
 				__u32		flags;
 			} netfilter;
+			struct {
+				union {
+					__u32	relative_fd;
+					__u32	relative_id;
+				};
+				__u64		expected_revision;
+			} tcx;
 		};
 	} link_create;
 
@@ -6197,6 +6226,19 @@ struct bpf_sock_tuple {
 	};
 };
 
+/* (Simplified) user return codes for tcx prog type.
+ * A valid tcx program must return one of these defined values. All other
+ * return codes are reserved for future use. Must remain compatible with
+ * their TC_ACT_* counter-parts. For compatibility in behavior, unknown
+ * return codes are mapped to TCX_NEXT.
+ */
+enum tcx_action_base {
+	TCX_NEXT	= -1,
+	TCX_PASS	= 0,
+	TCX_DROP	= 2,
+	TCX_REDIRECT	= 7,
+};
+
 struct bpf_xdp_sock {
 	__u32 queue_id;
 };
@@ -6479,6 +6521,10 @@ struct bpf_link_info {
 				} event; /* BPF_PERF_EVENT_EVENT */
 			};
 		} perf_event;
+		struct {
+			__u32 ifindex;
+			__u32 attach_type;
+		} tcx;
 	};
 } __attribute__((aligned(8)));